Process for imparting wool-like finish to cellulose-acid-nitrogen complex fabrics and product thereof



l1 2,709,638 rnocnss tron ll /lPARTlNG WOOL-LIKE FrNrsrr T (IELLULUSE-AClD-NITROGEN COMPLEX FABRECS AND PRODUCT THEREOF No Drawing. Application February 19, 1951, Serial No. 211,814

3 Claims. (U. 8-129) This invention relates to textile finishing and is con cerned with the finishing of cellulose fabrics, especially cotton fabrics, in a manner imparting to such fabrics certain altered and improved characteristics described hereinafter.

Perhaps the most outstanding alteration occurring as a result of the finishing process of this invention is the imparting to the cellulose fabric of a hand or feel which is similar to that of wood fabrics, the fabric being soft and flexible and having a warmth of feel ordinarily exhibited only by woolen fabrics. Indeed, with certain types of cotton goods the alteration toward a wool-like hand is so striking as to render the fabric distinguishable from similar wool fabrics only by careful inspection.

At the same time the finishing process of the invention imparts a substantial degree of crease resistance.

Still further the altered or improved characteristics in cluding the wool-like hand and crease resistance are of high durability, so as to withstand repeated washings or launderings without appreciable impairment. Indeed, in at least some instances, it is found that the Wool-like hand imparted by the finishing process of the present invention actually increases with repeated laundering.

Another important characteristic of the finish of the present invention is the fact that the altered characteristics are attained without appreciable impairment in the strength of the treated cloth and with relatively low take-on or increase in weight.

The finishing process of the invention is effective on all weights and constructions of cellulose and regenerated fabrics, including cotton and linen goods, and viscose rayon, suitable for clothing, dresses, drapes, and the like, inclusive of high twist and tightly woven fabrics.

The finishing process of the invention may be applied over the entire area of the fabric being treated or in limited areas thereof only, as in stripes or patterns, in which event still other advantageous characteristics in Fatenled i l/lay El, 1955 Before specifically considering the conditions of the treatment procedure of the present invention, and the permissible variations, an illustrative treatment will be briefly described. Thus, in a typical case, a cotton fabric is first impregnated with an aqueous solution of orthophosphoric acid and urea and the impregnated fabric is heated to effect reaction between the cellulose, the acid and the urea. The result of this reaction is the formation of a cellulose-acid-nitrogen complex. Following this reaction the fabric is treated with caustic soda under conditions providing for a second reaction in which sodium replaces nitrogen in molecules of the cellulose'acid-nitrogen complex. Thereafter substantially all free caustic soda is removed by washing and any remaining free caustic is neutralized by a souring treating. In this way a cellulose-acid-sodiurn complex is formed, and the fibers containing this so altered cellulose complex manifest strikingly different physical characteristics, as compared with the characteristics of the same untreated fibers. Moreover, because of the fact that the alteration is, so to speak, built into the substance of the fabric itself, the altered characteristics of the fabric are of exceptional durability.

In considering the ranges of treatment conditions and the like which re usable according to the present invention, it is first to be pointed out that in general the treatment to incorporate the sodium into the cellulose complex may be applied to fabrics previously treated with a wide variety of different materials for producing the cellulosc-acid-nitr0ge complex. Numerous specific ways of producing the cellulose-acid-nitrogcn complex are known, many examples being given in the issued patents of Ford and Hall Nos. 2,482,755, 2,482,756, and 2,524,783. Thus, as disclosed in Patents 2,482,755 and 2,482,756, a fabric is treated with various acids of phosphorous or sulfur and also with various nitrogen-containing compounds, the fabric being heated or baked in the presence of both the acid and the base under conditions effecting reaction with the cellulose. in accordance with the disclosure of said Patents 2,482,755 and 2,482,756, the specific acids and base materials and the quantities thereof are such as to produce a cellulose-acid-nitrogen complex having fiameproof characteristics. Celluloseacid-nitrogen complexes produced in accordance With said Patents 2,482,755 and 2,482,756 are usable in the further processing contemplated by the present invention, i. e., the treatment with caustic soda so as to substitute sodium in place of nitrogen in the complex.

the fabric a whole are obtained, as will further appear.

Various attempts have been made heretofore to alter the characteristics of cellulose fabrics in numerous ways increasing crease resistance or changing the hand of the fabric, but such prior processes have been subject to one or another of several disadvantages including especially serious impairment of strength, lack of adequate durability, etc. At least most of such prior treatments have involved the use of various thermosetting resins, which are applied to the fabric and then cured thereon so that they become mechanically interlocked with the fibers of the fabric. Treatments with caustic soda are also Well known, including treatment of resin impregnated fabric, the caustic soda being thereafter washed out.

in contrast with the foregoing, the finishing process of the present invention is accomplished in an entirely different way, involving a true chemical reaction with the cellulose itself, to thereby permanently alter the chemi cal structure of the cellulose of which the fabric is formed. In this way an exceptional degree of durability of the finish is attained.

Cellulose acid-nitrogcn complexes produced by the use of other acids and other nitrogen-containing compounds are also suitable for the further treatment of the present invention with caustic soda. For example, the celluloseacid-nitrogen complexes produced by treatments disclosed in Patent No. 2,524,783 may also be further treated with caustic soda according to the present invention in order to substitute sodium for nitrogen. In said Patent 2,524,- 783 a large number of acids and nitrogen-containing compounds are shown to be usable in the production of cellulose-acid-nitrogen complexes which are highly mildewproof.

Thus, it is already known to produce cellulose-acidnitrogen complexes by reaction of the cellulose with a very wide variety of acids and nitrogen-containing compounds, by applying heat or baking a fabric after application of the acid and nitrogen compound thereto; and the further treatment of the present invention is applicable to any cellulose fabric which has been pretreated in the ways just indicated.

It will be understood, of course, that the pretreatment with acid and nitrogen-containing compound should not be of such character as to destroy or extensively damage the fabric. For example it is known that strong halogen aroaess acid treatment, even in the presence of organic nitrogencontaining bases, will attack cellulose fibers so severely as to destroy the fabric. It will be obvious that the prod uct resulting from such destruction of the fabric is not usable according to the present invention, which requires treatment of the celluloseacid-nitrogen complex in fabric form.

From the foregoing it will be seen that the celluloseacid-nitrogen complex to be treated according to the present invention may be produced by a wide variety of pretreatments, with a wide variety of acids and nitrogencontaining compounds. To further illustrate this it may be mentioned that any acid (which will not destroy the fabric) may be used where the acid has at least two replaceable acid hydrogens providing for linking both with the cellulose and with the nitrogen, or any polyacid with at least three replaceable acid hydrogens may be employed provided not more than one acid hydrogen has been replaced by a metal. Examples of such acids are phosphoric acid, metaphosphoric acid, pyrophosphoric acid, ortho, metaand pyrophosphorus acids, phosphamic acid, phosphotungstic acid, sulfuric acid, sulfamic acid, phytic, and similarly relatively strongly effective acids. Also weaker acids may be used, such as malonic, phthalic, citric, pyroantimonic, dihydroxydiphenic, molybdic, tungstic, vanadic, telluric, selenic, and fiuosilicic. In fact any soluble dibasic acid, organic or inorganic, substantially non-volatile, which will react with the cellulose to replace hydroxyl groups may be used.

Metal salts and organic substituted salts of the acids having free acidity for combination both with the cellulose and the nitrogen supplied from the nitrogen-containing compound may also be used.

Cellulose-acid-nitrogen complexes made with the acids themselves, and especially with crthophosphoric, sulfuric or sulfarnic acid are preferred.

As already indicated, the cellulose-acid-nitrogen complex which may be treated according to the present invention may also be formed by the use of a variety of nitrogen-containing compounds. In general such compounds should be at least partially water soluble and should be basic toward the acid used. Urea is highly effective and other bases may be employed such as dicyandiamide, biuret, acetamide, cyanoacetamide, guanidine bicarbonate, aminoguanidine carbonate, biguanide, guanidine, or mixtures thereof.

The strength of the base is desirably varied according to the particular acid being used, the more strongly basic nitrogen-containing compounds being preferred where the stronger acids are at the same time used. Various bases may be used in combination or coniointly.

As above indicated, the fabric is heated or baked in the presence of both the acid and the nitrogen-containing compound in order to effect the reaction producing the complex with the cellulose. The temperature of baking may be varied between about 400 F. and 250 F. and the time from about one minute to about thirty minutes for commercial operation. Generally speaking, the lower the temperature the longer the time and vice versa. The concentration and strength of the acid are also factors determining the most desirable baking conditions. The greater the acidity on the cloth at the time of baking the less the temperature and time required to effect the reaction. and vice versa. The preferred temperature is from 270 F. to 350 F. and the preferred time from fifteen minutes to two minutes.

Fabrics containing a wide range of cellulose-acid-nitrogen complexes are usable according to the present invention, i. e., a Wide range both with respect to the particular acid and nitrogen-containing compounds employed and also with respect to the quantities and relative proportions thereof.

The acid and nitrogen-containing compound may either be applied to the fabric separately or in a common solution, preferably an aqueous solution. The concentration of the acid in the solution initially applied is not critical. While it is preferred to apply the desired amount of solids to the fabric with a single application of solution there may be several applications of the solution, followed with intermediate dryings. In the latter case a more dilute solution may be employed. For a single application of the solution with a substantially solution pick-up by weight of the fabric in the dry state, the concentration of orthophosphoric acid may run between 2% and 16% by weight of the solution. Up to about 30% acid is usable, but more than about 16% is not necessary.

The pH of the solution as applied is also not critical. The reaction between the acid and the cellulose during the baking or curing occurs only under acidic conditions. During the curing the pH on the cloth should be from 2 pH to 7 pH and preferably from 3 pH to 6 pH, as determined by indicator solutions. The pH of the solution itself may be higher and may even be on the alkaline side, providing that during the curing the pH comes down to the values just above given, as determined by indicator solutions. The urca is a weak base, i. e., change in amount used does not markedly affect pH. Hence, an excess of urea over that which will combine with the acid may be and is desirably used to make sure that there is plenty of buffering action, and this tends to reduce tendering of the fabric. Should the pH of the solution be too high to come down to the values above indicated, a small amount of acid may be added and contrariwise if the pH of the solution is too low, it may be corrected for by the addition of the needed amount of an alkaline neutralizing agent, prcferably organic bases such as guanidine, triethanolaminc, monoethanolamine, propanolamine, etc., but inorganic bases, such as caustic soda or potassium hydroxide, may also be used for this small adjustment provided they do not precipitate with the combining acid. When using weak bases such as urea, however, it is ordinarily unnecessary to add acid or basic materials to the solution. We prefer a range of urea to orthephosphoric acid of from 1 to 4 mols of urea to 1 mol of acid, although one may go as high as 10 mols of urea to 1 mol of acid if one does not regard the economic aspects, as the excess would in this case largely be wasted.

The preferred range of acid content, on the cloth hised on one application with 100% solution pick-up, is from 2% to 16% by weight of the cloth, with the urea ranging from 1 to 4 mols per mol of acid.

The quantities of acid and nitrogen-containing compound applied to the fabric and the conditions of treatlifil'lt are preferably such as to introduce an appreciable quantity of acid and nitrogen into the complex being formed. Considerable variation is, however, permissible, the important factor being the introduction of sufficient acid and nitrogen to provide for an appreciable subsequent reaction with the caustic soda and thereby produce a modified complex in which an appreciable quantity of sodium has been replaced for the nitrogen.

As disclosed in the above mentioned Ford ct a1. Pat" ent No. 2,482,755 (col. 20 commencing at line 6), in the case of the use of phosphoric acid, the quantity of acid content in the fabric, after baking, washing and drying, may range upwardly to an amount sufiicient to provide a content of 5% phosphorous in the complex which in terms of phosphoric acid is 15%. In the case of phosphoric acid, the quantity of acid present in the complex a may also range downwardly to about 1.5% which, as

disclosed in the parent application Serial No. 19,628, would provide a content of 0.5% phosphorus in the complex. The nitrogen content may range from about .5% to 6.0%, usually from about 1.4% to about 4.0%, by Weight of the fabric in the dry state.

The foregoing ranges are indicated as being those desirable for commercial use, but it should be kept in mind that some of the effect of the present invention is attained whenever some of the cellulose-acid-nitrogen compound is available for reaction with the caustic soda utilized in the treatment of the present invention.

The treatment of the present invention contemplates use of an aqueous solution of caustic soda and this treatment is advantageously effected at room temperature, although some variation from room temperature is, of course, permissible. A caustic soda solution is suitable and treatment for a period of time in the neighborhood of about seconds is appropriate. This is sufficient in most cases to obtain the desired substitution of sodium for nitrogen in the cellulose complex. The caustic concentration may vary at room temperature from approximately 10% to approximately and the time of treatment with caustic soda may vary from about 180 seconds to about 5 seconds. Even lower percentages of caustic will give some effect on cotton fabrics although to obtain pronounced effects on cotton fabrics requires upwards of about 10%. In the event of treatment of viscose rayon the concentration of the caustic is preferably kept quite low, most advantageously below 10%, and with this type of fabric appreciable effects are obtained even down to a concentration of about A% causic, although a percentage somewhat higher than this is preferred. On cotton fabrics the caustic concentration may even be carried beyond 50% although no appreciable improvement is obtained at these very high percentages.

For best results, immediately after this period of treatment with the caustic soda, the fabric should be carefully washed to remove most of the remaining free caustic soda. Such washing is advantageously effected with flowing water or by forcibly spraying and sucking water through the fabric. After the washing the pH of the fabric should be brought to the point of substantial neutrality. This may be done by employing a solution of sodium bicarbonate or similar acid salt. Since it is difficult if not impossible in commercial practice to completely remove free caustic soda by washing with water, this treatment is in effect a souring treatment, because it materially lowers the pH. The treatment with sodium bicarbonate also converts the remaining free caustic to sodium carbonate which latter is more easily washed from the fabric, to thereby attain substantial neutrality. An acid may also be used for this purpose, providing this is done with care to avoid lowering the pH below '7, and the use of an acid salt is preferred because the extent of acidification is more readily controlled when employing the salt. In some cases washing with water alone may be sufficient to remove all traces of caustic and thereby achieve a substantially neutral condition.

The foregoing treatment with caustic soda results in modification of the cellulose-acid-nitrogen complex to a cellulose-acidsodium complex, as is readily shown by various considerations and analyses.

The treatment with caustic soda may be effected in any one of a variety of ways adapted to apply the caustic over the entire area of the cloth, including immersion of the fabric in the caustic soda solution, padding the solution on the cloth, or printing the solution on the cloth. This treatment may be done while the fabric is either slack or under tension. When the fabric is treated slack appreciable shrinkage occurs and the wool-like hand of the treated fabric is accentuated. However, even when retaining the fabric under sufiicient tension to maintain the original width thereof, a very pronounced wool-like hand is secured.

The treatment with caustic soda may still further be effected by printing the solution on the cloth in patterns or in stripes, in which event the conversion of the cellulose-acid-nitrogen complex to a cellulose-acid-sodium complex occurs substantially only in the areas to which the caustic solution is applied. The washing applied to the fabric subsequent to the printing of the solution may, however, carry some caustic soda over b from the printed areas to the unprinted areas in which event limited modification of the cellulose complex in the unprinted areas may also occur and in some cases this is a desirable effect.

In the case of applying the caustic soda to the fabric in stripes, a highly advantageous fabric is: obtained by leaving the fabric slack during this treatment, the result being shrinkage of the fabric in the areas represented by the stripes in which the solution is applied, so that the intermediate areas become crinkled in the manner of seersucker. Still other special effects may be obtained Where the caustic soda is printed only in certain pattern areas, in which event shrinkage in the printed areas can be used to obtain contrasting appearance effects.

The treatment with caustic soda fully described above results in a substitution of sodium for nitrogen in the cellulose-acid-nitrogen complex. Similar effects may also be obtained by treatments with certain other compounds resulting in the substitution of sodium or even of certain other metals. The alternative compounds which are usable are agents having both swelling prop erties with reference to cellulose, and in addition having capability of reaction to effect metal substitution for the nitrogen. For example, instead of the treatment with caustic soda the fabric may be treated with caustic cupro-ammonium solution, or a caustic sodium zincate solution, or a concentrated calcium thiocyanate solution, or a super-cooled caustic soda solution, that is, one cooled to substantially -10 C. in the event of use of any of these compounds a similar substitution of a metal for nitrogen occurs. When using certain of these compounds, some variations in neutralizing treatments may be adopted. Thus, in the case of calcium thiocyanate the fabric may be brought to substantial neutrality merely by careful Washing.

Various softeners may also be applied to the fabric after the treatment with caustic soda, for instance a cationic softener such as Ahcovel G. Other conventional cationic active softeners may be used such, for example, as Sapamine KW (trimethyl ammonium methyl sulfate of monostearylmeth-phenylenc diamine), Triton K-60 (tetra allryl quaternary ammonium chloride), Amonyx T (trialkylbenzyl ammonium chloride), stearamidomethylpyridinium chloride, and stearyloxymethylpyridinium chloride. Non-permanent softeners may also be used such as sulfonated taliow, lecithin, sulfonated fatty chain alcohols, etc., but the permanent softeners are preferred.

To improve stability, aldehydes such for example as formaldehyde, may be incorporated in the acid and nitrogen-containing solution applied to the fabric in the pretreatment. The aldehydes should be employed in the ratio of from approximately .2 mols to approximately 3 mols of aldehyde to 1 mol of acid on the basis of phosphoric acid. Instead of formaldehyde, paraformaldehyde, hexamethylenetetramine, and glyoxal may be used. Aldehydes of higher molecular weight may be added, but the final results obtained are inferior and become more so With the increased molecular weight of the aldehyde.

Part or all of the aldehyde and some of the nitrogen compound may be replaced with a compound in which these two ingredients are already combined but are still in the water soluble state, such, for example, as urea-formaldehyde, urea-glyoxal, and melamine'formaldehydcresins, in the A stage. These may be added as a pretreatment of the fabric, in the way of a size or solution, followed by drying; or they may be added directly to the acid and nitrogen-containing solution. When added directly to the solution, it is desirable to add a volatile alkaline agent to temporarily adjust the pH of the solution to neutrality or slight alkalinity to prevent precipitation of the resin forming materials, as, for example, by adding ammonium hydroxide. During aroasss the curing, the ammonia will be driven off and the solution will become acid so that reaction with the cellulose will occur. It is to be understood when these materials are used, part of the acid will act as a catalyst and not enter into the reaction with the cellulose. Hence in such cases the acid content in the solution should be increased and the amount of acid over and above that required for catalytic purposes should be within the ranges heretofore given.

In connection with the caustic soda treatment of the invention it may be mentioned that wherever the caustic soda is to be applied over the entire area of the fabric, this may, if desired, be accomplished by the use of equipment commonly employed for mercerizing. It should be kept in mind, however, that the treatment of the invention is clearly distinguished from a mere mercerization. in the case of mercerization all of the caustic soda applied to the fabric is subsequently carried out of the fabric in the wash water and/ or by the neutralizing treatments. This is true even where the fabric being mercerized has been previously treated with a thermosetting resin.

In contrast with the above, the treatment of the celluloseacid-nitrogen complex with caustic soda, as contemplated by the present invention results in a reaction in which an appreciable part of the caustic soda is combined, and when the fabric treated according to the invention is subsequently washed to remove free caustic soda, it is found that the total amount which can be washed out is smaller than that initially applied, because that part combined with the cellulose is permanently bound thereto.

It may also be mentioned that tests show that the nitrogen content of the fabric after treatment with the caustic soda is reduced from a typical initial value of about 3 /2%, down to a fraction of 1%, even as low as about Still further, tests show that sodium is present in the treated fabric.

Example I The fabric treated according to the present example was a 40"80/80-3.50-printed cotton fabric. The cellulose of this fabric was converted to a cellulose-acidnitrogen complex by pretreatment including impregnation with the following solution, squeezing, drying, and then baking for 6 minutes at 320 F, followed by washing and drying:

60.0 lbs. orthophosphoric acid (75%) 40.0 lbs. dicyandiamide 120.0 lbs. urea 60.0 lbs. mill ammonia (28%) 80.0 lbs. formaldehyde (37%) 100 gallons with water The solution was prepared by first heating together the phosphoric acid and the dicyandiamide and 60 lbs. of water. When the violent reaction subsided, 120 lbs. of urea and enough water to make 80 gals. was added. The ammonium hydroxide was then added and finally the formaldehyde.

The fabric prepared according to the foregoing was then treated with caustic soda according to the present invention. In this instance the caustic soda was applied in a mercerizing machine, using 60 Tw. (30%) caustic soda solution. The cloth was thoroughly washed with warm water on the frame while under tension and then washed with a sodium bicarbonate solution in the wash boxes on the mercerizer. After further washing, the cloth was squeezed and dried. The fabric was finally thoroughly impregnated with a 2% solution of a cationic softener (Ahcovel G), squeezed, and dried.

The finished fabric had excellent strength, was very crease resistant, and had a flexible, full, soft and strikingly wool-like hand. it finished at the normal width of the fabric with satisfactory shrinkage.

Example II The fabric treated according to the present example was a "48/482.85 yds/lb-printed cotton fabric.

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150.0 lbs. orthophosphoric (75%) 100.0 lbs. dicyandiamide 300.0 lbs. urea 24.0 lbs. guanidine carbonate 100 gallons with water The solution was prepared as in Example I.

The fabric prepared according to the foregoing was then treated with caustic soda according to the present invention. In this instance the caustic soda was applied in a mercerizing machine, impregnating with 100 Tw. caustic soda solution and squeezing, followed by stretching in the clip mercerizing frame. While in the frame the fabric Was first washed with warm water and then with a sodium bicarbonate solution. The fabric was further washed, first in sodium bicarbonate solution and then in water until the caustic was removed. It was then squeezed and impregnated with a 2% solution of lecithin, squeezed, and dried.

The resulting fabric was crease resistant, had a full soft, wooly hand, was highly flexible and finished at the normal with of the fabric (35%") and with satisfactory shrinkage characteristics when subjected to a soap test. The tensile and tearing strength of the fabric was very satisfactory.

Example III A printed, sateen, cotton cloth was treated according to the present invention. The cellulose of this fabric was first converted to a cellulose-acid-nitrogen complex by pretreatment including impregnation with the following solution, squeezing, drying and then baking for 8 minutes at 340 F., followed by washing and drying:

35.0 lbs. orthophosphoric acid 23.0 lbs. dicyandiamide 70.0 lbs. urea 25.0 lbs. mill ammonia (28%) 45.0 lbs. formaldehyde (37%) gallons with water The solution was prepared as in Example I.

The fabric was then treated with caustic soda, washed, dried, and softened as described in Example I. The finished fabric had a soft, full, wool-like hand.

The foregoing treatment was duplicated except that the cure was for 4 minutes at the same temperature instead of 8 minutes, and this also provided the desired fabric finish.

Example IV 100 gallons with water The solution was prepared as in Example I. The fabric prepared according to the foregoing was then treated with a 10% solution of caustic soda according to the present invention by impregnation and squeezing, and then washed with water under tension in the mercerizing machine. This was followed by aromas 9 washing in sodium bicarbonate solution and then in water. After a thorough squeeze, the fabric was impregnated with a 2% solution of trimethyl ammonium methyl sulfate of monostearylmeth-phenylene diamine (Sapamine K W) and dried.

The finished fabric had a wool-like flexible, full, soft hand with good crease resistance and good strength.

Example V The fabric treated according to the present example was a 40", 64/64, 9.00 yds./lb., cotton voile fabric. The cellulose of this fabric was converted to a cellulose-acidnitrogen complex by pretreatment including impregnation with the following solution, squeezing, drying, and then baking for 6 minutes at 320 F.

60.0 lbs. orthophosphoric acid (75%) 40.0 lbs. dicyandiamide 120.0 lbs. urea 54.0 lbs. mill ammonia (28%) 100.0 lbs. Aerotex M-3 (methyl-methylol melamine resin 100 gallons with water The solution was prepared as in Example I. The cured fabric without washing was treated with caustic soda as described in Example I and after washing and drying, was treated with a solution of Triton K-60 (tetralkyl quaternary ammonium chloride) and finally dried.

The finished fabric had a full soft wool-like hand and was of good strength and stability.

Example VI The cellulose of a cotton fabric was converted to a cellulose-acid-nitrogen complex by pretreatment as in Example I using:

100.0 lbs. orthophosphoric acid 200.0 lbs. biuret 25.0 lbs. ammonium hydroxide 25.0 lbs. formaldehyde 100 gallons with water The fabric prepared according to the foregoing was then treated with a cupro-amrnonium solution by impregnation for 60 seconds in a mercerizing machine and washed under tension with Warm water and then with acetic acid and then with water. The fabric was finally squeezed well and then impregnated with Sapamine KW (trirnethyl ammonium methyl sulfate of monostearylmeth-phenylene diamine), squeezed and dried. The desired wool-like hand was obtained.

The cupro-ammonium solution was prepared by the usual methods using the formula:

60.0 lbs. Cu. S()4-5H2O 375.0 lbs. mill ammonia (28% 56.0 lbs. caustic soda (28%) 120 gallons with water Example VII Example VIII A cotton fabric was presized, dried, cured, washed and dried as described in Example I, to convert the cellulose to a cellulose-acid-nitrogen complex.

The fabric, thus prepared, was then treated in a continuous open soaper machine, first with caustic soda (30% sol.) for a period of 15 seconds followed by a treatment in sulfuric acid solution to substantial neutrality, care being taken that the pH of the fabric does not fall below pH 7; this again was followed by a thorough washing in water. The cloth was dried and then treated with a 1% solution of stearamidomethylpyridinium chlo ride and then dried.

A crease resistant, soft, flexible fabric with a wool-like hand was obtained.

Example IX A cotton fabric was converted to a cellulose-acidnitrogen by pretreatment including impregnation with the following solution, squeezing, drying and then baking, washing and drying.

200.0 lbs. sulphamic acid 200.0 lbs. urea 100 gallons with Water The fabric prepared according to the foregoing was then treated with caustic soda, washed, neutralized, washed, dried, softened, and dried as described in Example I.

A fabric of good crease resistance, strength, stability and with a soft wool-like hand was obtained.

Example X A printed, sateen, cotton cloth was converted to a cellulose-acid-nitrogen complex by pretreatment including impregnation with the following solution, squeezing, etc., as described in Example I.

35 .0 lbs. orthophosphoric acid 23.0 lbs. dicyandiamide 70.0 lbs. urea 25.0 lbs. mill ammonia (28%) 45.0 lbs. formaldehyde (37%) gallons with water After drying the cloth was cured 2 minutes at 400 F. followed by washing and drying.

The fabric was then treated with caustic soda, washed, dried and softened as described in Example I.

A strong crease-resistant fabric was obtained which had a soft, flexible, wool-like hand.

Example X I A cotton fabric was converted to a cellulose-acidnitrogen complex by pretreatment including impregnation with the following solution, dried, cured, washed and dried as described in Example 1'.

250.0 lbs. monosodium phosphate 400.0 lbs. urea 100 gallons with water I It was then treated with caustic soda, washed, neutralized, washed, squeezed, and dried, and then softened and dried as described in Example I.

The resulting fabric had a flexible, full, soft and wool like hand.

Example XII The fabric thus prepared was then treated with caustic soda, washed, neutralized, washed, and dried, and finally softened and dried as described in Example I.

The resulting fabric had a pleasing, soft, wool-like hand.

Example XIII 100 gallons with water The fabric was then treated with caustic soda, washed, dried and softened as described in Example I.

A strong fabric with a full, flexible, soft wool-lik hand was obtained.

Example XIV A cotton fabric was treated as described in Example I, except that the impregnating solution had the following composition:

75.0 lbs. orthophosphoric acid (75%) 50.0 lbs. dicyandiamide 50.0lbs. Aerotex M3 (methylmethylol melamine resin 150.0 lbs. urea 60.0 lbs. mill ammonia (28%) 50.0 lbs. urea-formaldehyde resin 100 gallons with water I Example XV A 40"-48/483.50 yds./lb. linen fabric was treated as described in Example I and a crease resistant fabric of good strength and a wool-like hand was obtained.

Example XVI The fabric treated according to the present invention was a 40"48/48-2.85 yds./ 1b., printed cotton fabric.

The cellulose of this fabric was converted to a cellulose-acid-nitrogen complex in the same manner as in Example I.

The fabric was then treated with a sodium zincate solution made up as follows:

500 lbs. caustic soda (100 Tw.) 100 lbs. zinc oxide 100 gallons-total volume in the above the zinc oxide is dissolved in the hot caustic solution and water added with cooling to a total volume of 100 gallons.

The method of application and procedure was the same as in Example 1, including the final finishing treatment with softeners.

The resulting fabric had a durable wooly hand that was crease resistant and highly flexible.

Example XVII The fabric treated was an all viscose rayon 40 /2"- 3464-237.

The conversion of the cellulose was accomplished in accordance with Example I.

The subsequent treatment utilized at 10 TW. caustic solution and the same general procedure as in Example I, including the final finishing treatment with softeners.

The resulting fabric had a permanent weighty, woollike, scroopy hand. It was also highly crease resistant.

Example XVIII The fabric was a 39"80/804.00 pure cotton.

he procedure for the conversion of the cellulose was the same as in Example I.

The subsequent procedure consisted of applying a caustic treatment on a regular printing machine using an overall pad rolier. The printing paste had the following composition:

265 lbs. caustic soda (100%) lbs. converted starch (Bz' gum) gallons After printing the fabric was folded into boxes. The fabric was permitted to remain slack in the boxes for about an hour. It was then washed in rope form in a Rock wascr using hot water in a countercurrent flow. The next step consisted of a soaping treatment in about 2% soap solution at approximately F. for 20 minutes in rope form followed by rinsing, scutching, and slack drying. impregnation with 2% of Sapamine was followed by slack drying and short framing to 34 /2" finished width, completed the process.

The resulting fabric had a mellow wool-like hand. It was highly crease resistant and had good draping qualities. The finished fabric had satisfactory shrinkage characteristics and all the qualities were durable to repeated launderings.

Example XIX a The fabric treated was a 38 /2"64/605.35 pure cotton.

The conversion of the cellulose was done in the same manner as in Example I.

The subsequent procedure was the same as in Example XVIII except that the printing roller was a striped roller instead of the overall pad. The method of operation otherwise was the same as in Example XVIII, including the slack handling, softening and finishing.

The resulting fabric was a crinkled material having an unusually supple and wool-like hand with high resiliency. The effects as Well as the hand and drape of the fabric were durable to laundering.

This application is a continuation in part of application Serial No. 19,628, filed April 7, 1948, now abandoned.

We claim:

1. The process of imparting a durable wool-like hand to nitrogen-containing cellulosic fabrics which comprises effecting a metal for nitrogen substitution reaction by treatment of a fabric formed of a cellulose-acid-nitrogen complex composed of basic organic nitrogen compound and an acid having at least two replaceable acid hydrogens, the nitrogen compound being linked to the acid by replacement of one of said hydrogens and the acid being linked to the cellulose at a hydroxyl group of the cellulose molecule by replacement of another of said acid hydrogens, said complex containing by weight from 1.5% to 15% of acid and from 0.5% to 6% of nitrogen; the treatment comprising impregnating said cellulose-acid-nitrogen complex with an aqueous solution containing from to 50% of at least one cellulose chemical swelling agent selected from the group consisting of caustic soda, caustic cuproammonium and caustic sodium zincate, at a temperature between -l0 C. and room temperature, the solution of said swelling agent being retained in contact with the fabric for a suflicient time to reduce the nitrogen content of the 13 complex to between 4% and 1%; and thereafter washing and neutralizing the fabric.

2. The process of claim 1 for imparting a durable woollike hand to a cotton base complex in which the swelling agent solution contains from 10% to 50% caustic soda.

3. The process of claim 1 for imparting a durable woollike hand to a viscose rayon base complex in which the swelling agent solution contains from 0.25% to 10% caustic soda.

4. The process of claim 1 in which the treatment of the fabric with the swelling agent is effected while maintaining the fabric under tension.

5. The process of claim 1 in which the treatment of the fabric with a swelling agent is effected while allowing the fabric to shrink.

6. The process of claim 1 in which the treatment of the fabric with the swelling agent is applied only to limited areas of the field and in which such treatment the fabric is allowed to shrink.

7. The wool-like cellulosic textile fabric produced by the process of claim 1.

8. The wool-like cellulosic textile fabric produced by the process of claim 2.

References Cited in the file of this patent UNITED STATES PATENTS 1,666,083 Bodmer Apr. 17, 1928 2,158,494 Corteen et al. May 16, 1939 2,286,726 Gordon June 16, 1942 2,459,222 Guthrie Jan. 19, 1949 2,473,308 Stallings June 14, 1949 2,482,755 Ford et al. Sept. 27, 1949 2,482,756 Ford et al. Sept. 27, 1949 2,524,783 Ford et al Oct. 10, 1950 2,530,261 Morton et al. Nov. 14, 1950 2,603,551 Ward et al. July 15, 1952 FOREIGN PATENTS 634,690 Great Britain Mar. 22, 1950 OTHER REFERENCES 

1. THE PROCESS OF IMPARTING A DURABLE WOOL-LIKE HAND TO NITROGEN-CONTAINING CELLULOSIC FABRICS WHICH COMPRISES EFFECTING A METAL FOR NITROGEN SUBSTITUTION REACTION BY TREATMENT OF A FABRIC FORMED OF A CELLULOSE-ACID-NITROGEN COMPLEX COMPOSED OF A BASIC ORGANIC NITROGEN COMPOUND AND AN ACID HAVING AT LEAST TWO REPLACEABLE ACID HYDROGENS, THE NITROGEN COMPOUND BEING LINKED TO THE ACID BY REPLACEMENT OF ONE OF SAID HYDROGENS AND THE ACID BEING LINKED TO THE CELLULOSE AT A HYDROXYL GROUP OF THE CELLULOSE MOLECULE BY REPLACEMENT OF ANOTHER OF SAID ACID HYDROGENS, SAID COMPLEX CONTAINING BY WEIGHT FROM 1.5% TO 15% OF ACID AND FROM 0.5% TO 6% OF NITROGEN; THE TREATMENT COMPRISING IMPREGNATING SAID CELLULOSE-ACID-NITROGEN COMPLEX WITH AN AQUEOUS SOLUTION CONTAINING FROM 1/4% TO 50% OF AT LEAST ONE CELLULOSE CHEMICAL SWELLING AGENT SELECTED FROM THE GROUP CONSISTING OF CAUSTIC SODA, CAUSTIC CUPROAMMONIUM AND CAUSTIC SODIUM ZINCATE, AT A TEMPERATURE BETWEEN -10* C. AND ROOM TEMPERATURE, THE SOLUTION OF SAID SWELLING AGENT BEING RETAINED IN CONTACT WITH THE FABRIC FOR A SUFFICIENT TIME TO REDUCE THE NITROGEN CONTENT OF THE COMPLEX TO BETWEEN 1/4% AND 1%; AND THEREAFTER WASHING AND NEUTRALIZING THE FABRIC. 